Continuity-detecting method of dispensing particles, a particle filling line and apparatus for dispensing particles

ABSTRACT

A particle filling line comprises a vertically-oriented conduit that includes a conduit hollow. The conduit includes a conduit top and a conduit bottom. The conduit bottom defines an outlet. The conduit is arranged so that particles supplied to the conduit top flow through the outlet to be received by one or more containers disposed on a movable conveyor belt. The conduit hollow includes one or more conduit hollow elements disposed therein. The one or more conduit hollow elements include any of a plurality of agitators and an auger. The particle filling line is arranged for determining a resistance that is based on the spacing between the one or more conduit hollow elements and the conduit inner walls. When the resistance is determined to be less than a threshold resistance value, the particle filling process ceases.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims the benefit under 35 U.S.C. §120 as a divisional of presently pending U.S. patent application Ser. No. 11/247,057 entitled “CONTINUITY-DETECTING METHOD OF DISPENSING PARTICLES FILLING LINE AND APPARATUS FOR DISPENSING PARTICLES”, filed Oct. 11, 2005, the entire teachings of which are incorporated herein by reference.

INCORPORATION BY REFERENCE OF A U.S. PATENT

The disclosure of the following U.S. patent hereby is incorporated by reference, verbatim, and with the same effect as though the same disclosure were fully and completely set forth herein: U.S. Pat. No. 6,889,722 B2, “Method of dispensing particles, a particle filling line, and apparatus for dispensing particles”, issued 10 May 2005 to Timothy L. Huss, the same individual as the present applicant, which patent is assigned to Xerox Corporation, the same assignee as in the present application.

BACKGROUND OF THE INVENTION

Any metal-to-metal contact in a toner filler can cause toner to be fused together into a toner flake or large toner particle. This metal-to-metal contact can be caused by improper set-up, a bent auger or equipment wear and tear. For example, this problem recently occurred at a toner plant where a bent auger that was not noticed caused toner flakes over a period of time that resulted in many customer complaints. Also, as a result of this problem, a substantial quantity of finished product is required to be scrapped or reworked. Auger and agitator contact to the funnel and hopper walls can happen intermittently due to the density variations of the material causing the agitator to flex outward, putting lateral forces on the auger shaft, or both. Setting up auger alignment on filler systems is a tedious task and is difficult to verify. Thus, there is a need for the present invention.

BRIEF SUMMARY OF THE INVENTION

In a first aspect of the invention, there is described a method of dispensing particles, the method comprising providing a vertically-oriented conduit having a conduit hollow, a conduit top and a conduit bottom, the conduit bottom defining an outlet; the conduit arranged so that particles supplied to the conduit top flow through the outlet; the conduit hollow including one or more conduit hollow elements disposed therein; the method further comprising (a) filling the conduit hollow with particles; (b) flowing the particles through the outlet to be received by one or more included containers; and (c) determining a resistance that is based on the spacing between the one or more conduit hollow elements and the included conduit inner walls.

In a second aspect of the invention, there is described a particle filling line comprising a vertically-oriented conduit having a conduit hollow, a conduit top and a conduit bottom, the conduit bottom defining an outlet; the conduit arranged so that particles supplied to the conduit top flow through the outlet; the conduit hollow including one or more conduit hollow elements disposed therein; the particle filling line arranged to fill one or more included containers with particles in accordance with a method comprising (a) filling the conduit hollow with particles; (b) flowing the particles through the outlet to be received by the one or more containers disposed on an included movable conveyor belt; and (c) determining when a resistance that is based on the spacing between the one or more conduit hollow elements and the included conduit inner walls is less than a threshold resistance value.

In a third aspect of the invention, there is described apparatus for dispensing particles comprising a vertically-oriented conduit having a conduit hollow, a conduit top and a conduit bottom, the conduit bottom defining an outlet; the conduit arranged so that particles supplied to the conduit top flow through the outlet; the conduit hollow including one or more conduit hollow elements disposed therein; the conduit being arranged with an included means for determining a resistance that is based on the spacing between the one or more conduit hollow elements and the included conduit inner walls.

BRIEF DESCRIPTION OF THE DRAWING

The drawing depicts a particle filling line comprising a vertically-oriented conduit 100. As shown, the conduit 100 includes a conduit hollow 3, a conduit top 10 and a conduit bottom 49. In turn, the conduit bottom 49 defines a conduit outlet 4. The conduit hollow 3 includes one or more conduit hollow elements 70, 80, 90 disposed therein. The one or more conduit hollow elements 70,80,90 comprise any of a plurality of agitators 70,80 and an auger 90. As shown, the conduit is arranged with an included resistance determining means 300. In turn, the resistance determining means 300 comprises a detector 310, a first detector path 301 and a second detector path 302. Also shown are one or more included containers 50 disposed on an included movable 61 conveyor belt 60.

DETAILED DESCRIPTION OF THE INVENTION

Briefly, a particle filling line comprises a vertically-oriented conduit that includes a conduit hollow. The conduit includes a conduit top and a conduit bottom. The conduit bottom defines an outlet. The conduit is arranged so that particles supplied to the conduit top flow through the outlet to be received by one or more included containers disposed on a movable conveyor belt. The conduit hollow includes one or more conduit hollow elements disposed therein. The one or more conduit hollow elements include any of a plurality of agitators and an auger. The particle filling line is arranged for determining a resistance that is based on the spacing between the one or more conduit hollow elements and the conduit inner walls. When the resistance is determined to be less than a threshold resistance value, the particle filling process ceases.

Referring now to the drawing there is depicted a particle filling line comprising a vertically-oriented conduit 100. As shown, the conduit 100 includes a conduit hollow 3, a conduit top 10 and a conduit bottom 49. In turn, the conduit bottom 49 defines a conduit outlet 4.

As shown, in one embodiment the conduit 100 includes an upper cylindrical portion 20, a middle conical portion 30, and a lower cylindrical portion 40. This lower cylindrical portion 40 is also commonly known and referred to as a “funnel”.

As depicted in the drawing, the conduit 100 is arranged so that particles 1 supplied 2 to the conduit top 10 flow in a downward direction 9 through the conduit hollow 3. Ultimately the particles 1 exit the conduit 100 through the conduit outlet 4.

As shown, the conduit hollow 3 includes one or more conduit hollow elements disposed therein, where the one or more conduit hollow elements comprise any of the depicted first agitator 70, second agitator 80 and auger 90.

Still referring to the drawing, the particle filling line is arranged to fill one or more included containers 50 with particles 1 in accordance with a method. The method comprises (a) filling 2 the conduit hollow 3 with particles 1; (b) flowing the particles 1 through the outlet 4 to be received 5 by the one or more included containers 50 disposed on an included movable 61 conveyor belt 60; and (c) determining, by means of the resistance determining means 300, a resistance that is based on the spacing 72, 73, 83, 94 between the one or more conduit hollow elements 70, 80 and 90 and the included conduit inner walls 21, 31, 41. When the resistance determining means 300 determines that the resistance is less than a threshold resistance value, the particle filling process ceases.

For good understanding, as used herein, the term “resistance” refers to electrical resistance. As is known, electrical resistance is a property of a conductor by virtue of which the passage of electric current is opposed, thereby causing electric energy to be transformed into heat, and equal to the voltage across the conductor divided by the current flowing in the conductor, commonly measured in ohms.

As shown, in one embodiment, the aforementioned spacing between the one or more conduit hollow elements 70, 80, 90 and the included conduit inner walls 21, 31, 41 comprises at least the following four (4) depicted spacings: a first spacing 72 between the first agitator 70 and the conduit inner wall 21; a second spacing 73 between the first agitator 70 and the conduit inner wall 31; a third spacing 83 between the second agitator and the conduit inner wall 31; and a fourth spacing 94 between the auger 90 and the conduit inner wall 41.

As depicted, the conduit 100 is arranged with an included resistance determining means 300. In turn, the resistance determining means 300 comprises a detector 310, a first detector path 301 and a second detector path 302.

As shown, in one embodiment the one or more conduit hollow elements comprise any of the first agitator 70, the second agitator 80 and the auger 90.

In another embodiment, the one or more conduit hollow elements comprise anyone element of the first agitator 70, the second agitator 80 and the auger 90.

In a further embodiment, the one or more conduit hollow elements comprise any two elements of the first agitator 70, the second agitator 80 and the auger 90.

In still another embodiment, the one or more conduit hollow elements comprise all three elements of the first agitator 70, the second agitator 80 and the auger 90.

In one embodiment the method includes, based on the resistance determining means 300 determining that the resistance is less than a threshold resistance value, ceasing the flow of particles 1 through the outlet 4 to be received 5 by the one or more containers 50.

Still referring to the drawing, in a first embodiment the one or more conduit hollow elements 70, 80, 90 and the conduit 100 are comprised of a conductive material and the method includes determining, by the resistance determining means 300, when the resistance between any of the one or more conduit hollow elements 70, 80, 90 and any of the conduit inner walls 21, 31, 41 is less than a threshold resistance value.

In one application of the foregoing first embodiment, for example, the first detector path 301 is coupled to any of the depicted contact points labeled “U”, “V” and “T” and the second detector path 302 is coupled to the depicted contact point labeled “Y”. As shown in the drawing, the contact points U, V and T respectively correspond to the first agitator 70, the second agitator 80 and the auger 90; and the contact point Y corresponds to the conduit inner wall 21.

Referring still to the drawing, in a second embodiment the one or more conduit hollow elements 70, 80, 90 are coupled to an included power drive 200; the one or more conduit hollow elements 70,80,90, the power drive 200 and the conduit 100 are comprised of a conductive material; and the method includes determining, by resistance determining means 300, when the resistance between the power drive 200 and any of the included conduit outer walls 22, 32, 42 is less than a threshold resistance value.

In one application of the foregoing second embodiment, for example, the first detector path 301 is coupled to the depicted contact point labeled “W” and the second detector path 302 is coupled to the depicted contact point labeled “Z”. As shown in the drawing, the contact point W corresponds to the power drive 200 and the contact point Z corresponds to the conduit outer wall 22.

Still referring to the drawing, in a third embodiment the one or more conduit hollow elements 70, 80, 90 are coupled to an included power drive housing 210; the one or more conduit hollow elements 70, 80, 90, the power drive housing 210 and the conduit 100 are comprised of a conductive material; and the method includes determining, by the resistance determining means 300, when the resistance between the power drive housing 210 and any of the included conduit outer walls 22, 32,42 is less than a threshold resistance value.

In one application of the foregoing third embodiment, for example, the first detector path 301 is coupled to the depicted contact point labeled “X” and the second detector path 302 is coupled to the contact point Z. As shown in the drawing, the contact point X corresponds to the power drive housing 210 and the contact point Z corresponds to the conduit outer wall 22.

In one embodiment the particles 1 comprise toner.

In one embodiment the threshold resistance value is 10 ohms.

Thus, there is described the first embodiment, namely, a method of dispensing particles 1, the method comprising providing a vertically-oriented conduit 100 having a conduit hollow 3, a conduit top 10 and a conduit bottom 49, the conduit bottom 49 defining an outlet 4; the conduit 100 arranged so that particles 1 supplied 2 to the conduit top 10 flow 9 through the outlet 4; the conduit hollow 3 including one or more conduit hollow elements disposed therein; the method further comprising (a) filling 2 the conduit hollow 3 with particles 1; (b) flowing the particles 1 through the outlet 4 to be received 5 by one or more included containers 50; and (c) determining, by the included resistance determining means 300, a resistance that is based on the spacing 72, 73, 83, 94 between the one or more conduit hollow elements and the included conduit inner walls 21, 31, 41.

The following eight (8) sentences labeled A through H apply to the foregoing first aspect of the invention:

A. In one embodiment the one or more conduit hollow elements comprise a first agitator 70, a second agitator 80 and an auger 90.

B. In one embodiment the method includes, based on the resistance determining means 300 determining that the resistance is less than a threshold resistance value, ceasing the flow of 1 through the outlet 4 to be received 5 by the one or more containers 50.

C. In one embodiment the one or more conduit hollow elements 70, 80, 90 and the conduit 100 are comprised of a conductive material; and the method includes determining, by the resistance determining means 300, when the resistance between any of the one or more conduit hollow elements 70, 80, 90 and any of the conduit inner walls 21, 31, 41 is less than a threshold resistance value.

D. In one embodiment the one or more conduit hollow elements 70, 80, 90 are coupled to an included power drive 200; the one or more conduit hollow elements 70, 80, 90, the power drive 200 and the conduit 100 are comprised of a conductive material; and the method includes determining, by the resistance determining means 300, when the resistance between the power drive 200 and any of the included conduit outer walls 22, 32, 42 is less than a threshold resistance value.

E. In one embodiment the one or more conduit hollow elements 70, 80, 90 are coupled to an included power drive housing 210; the one or more conduit hollow elements 70, 80, 90, the power drive housing 210 and the conduit 100 are comprised of a conductive material; and the method includes determining, by the resistance determining means 300, when the resistance between the power drive housing 210 and any of the included conduit outer walls 22, 32, 42 is less than a threshold resistance value.

F. In one embodiment the particles 1 comprise toner.

In one embodiment the threshold resistance value is 10 ohms.

H. In one embodiment the method comprises detecting a metal-tometal continuity between the conduit 100 and the one or more conduit hollow elements 70, 80, 90.

Also, there is described the second aspect of the invention, namely, a particle filling line (as depicted in the drawing) comprising a vertically-oriented conduit 100 having a conduit hollow 3, a conduit top 10 and a conduit bottom 49, the conduit bottom 49 defining an outlet 4; the conduit 100 arranged so that particles 1 supplied 2 to the conduit top 10 flow 9 through the outlet 4; the conduit hollow 3 including one or more conduit hollow elements disposed therein; the particle filling line arranged to fill one or more included containers 50 with particles 1 in accordance with a method comprising (a) filling 2 the conduit hollow 3 with particles 1; (b) flowing the particles 1 through the outlet 4 to be received 5 by the one or more containers 50 disposed on an included movable 61 conveyor belt 60; and (c) determining, by the included resistance determining means 300, when a resistance that is based on the spacing 72, 73, 83, 94 between the one or more conduit hollow elements and the included conduit inner walls 21,31,41 is less than a threshold resistance value.

The following six (6) sentences labeled I through N apply to the foregoing second aspect of the invention:

I. In one embodiment the one or more conduit hollow elements comprise a first agitator 70, a second agitator 80 and an auger 90.

J. In one embodiment the one or more conduit hollow elements 70, 80, 90 and the conduit 100 are comprised of a conductive material; and the resistance is determined, by the resistance determining means 300, between any of the one or more conduit hollow elements 70, 80, 90 and any of the conduit inner walls 21, 31, 41.

K. In one embodiment the one or more conduit hollow elements 70, 80, 90 are coupled to an included power drive 200; the one or more conduit hollow elements 70, 80, 90, the power drive 200 and the conduit 100 are comprised of a conductive material; and the resistance is determined, by the resistance determining means 300, between the power drive 200 and any of the included conduit outer walls 22,32,42.

L. In one embodiment the one or more conduit hollow elements 70, 80, 90 are coupled to an included power drive housing 210; the one or more conduit hollow elements 70, 80, 90, the power drive housing 210 and the conduit 100 are comprised of a conductive material; and the resistance is determined, by the resistance determining means 300, between the power drive housing 210 and any of the included conduit outer walls 22, 32,42.

M. In one embodiment the particles 1 comprise toner.

N. In one embodiment the threshold resistance value is 10 ohms.

Also, there is described the third embodiment, namely, apparatus for dispensing particles 1 comprising a vertically-oriented conduit 100 having a conduit hollow 3, a conduit top 10 and a conduit bottom 49, the conduit bottom 49 defining an outlet 4; the conduit 100 arranged so that particles 1 supplied 2 to the conduit top 10 flow 9 through the outlet 4; the conduit hollow 3 including one or more conduit hollow elements disposed therein; the conduit 100 being arranged with the resistance determining means 300 for determining a resistance that is based on the spacing 72, 73, 83, 94 between the one or more conduit hollow elements and the included conduit inner walls 21,31,41.

The following six (6) sentences labeled 0 through T apply to the foregoing third aspect of the invention:

O. In one embodiment the one or more conduit hollow elements comprise a first agitator 70, a second agitator 80 and an auger 90.

P. In one embodiment the one or more conduit hollow elements 70, 80, 90 and the conduit 100 are comprised of a conductive material and the resistance determining means 300 determines when the resistance between any of the one or more conduit hollow elements 70, 80, 90 and any of the conduit inner walls 21, 31, 41 is less than a threshold resistance value.

Q. In one embodiment the one or more conduit hollow elements 70, 80, 90 are coupled to an included power drive 200; the one or more conduit hollow elements 70, 80, 90, the power drive 200 and the conduit 100 are comprised of a conductive material; and the resistance determining means 300 determines when the resistance between the power drive 200 and any of the included conduit outer walls 22,32,42 is less than a threshold resistance value.

R. In one embodiment the one or more conduit hollow elements 70, 80, 90 are coupled to an included power drive housing 210; the one or more conduit hollow elements 70, 80, 90, the power drive housing 210 and the conduit 100 are comprised of a conductive material; and the resistance determining means 300 determines when the resistance between the power drive housing 210 and the included conduit outer walls 22, 32, 42 is less than a threshold resistance value.

S. In one embodiment the particles 1 comprise toner.

T. In one embodiment the threshold resistance value is 10 ohms.

In summary, this invention uses a continuity check between the rotating auger and agitators and the stationary fill hopper and funnel walls. The continuity tester can be tied in to the filler controls so if any metal-to-metal contact is made by the agitator or auger, the filling equipment will shut down and an alarm message displayed. To enable the continuity test from a technical aspect, the agitators, auger, auger coupling, quill/bearing assembly, and power drive motors are all bonded (or of the same potential by metal-to-metal fasteners) but are isolated (insulated) from the fill hopper, funnel and the rest of the filler system. This bonding from the filler/funnel and the auger/agitator are brought back to two separate ground or earth points. The tiny amount of power used in the continuity tester cannot transfer between the two ground or earth points but will easily be triggered by any metal-to-metal contact between the filler/funnel and the auger/agitator.

For good understanding, the aforementioned two separate ground or earth points are not expressly included in the drawing.

In one embodiment, for the auger/agitator to form metal-to-metal contact with the filler/funnel, the continuity test is based on determining that the electrical path from the auger/agitator to the filler/funnel comprises a resistance of less than ten (10) ohms. Hence, the metal-to-metal continuity determination is based on determining when the resistance between the auger/agitator and the filler/funnel is less than a threshold resistance value of ten (10) ohms. Based on Ohm's Law, this equates to a current range of from 5 to 50 milli-Amperes (“mA”), with a corresponding voltage range of less than 500 milli-Volts (“mV”), or 0.5 Volts.

In one embodiment, an intrinsically safe continuity test system for hazardous areas including gases is used.

Hence, a particle filling line as depicted in the drawing comprises a vertically-oriented conduit 100 that includes a conduit hollow 3. The conduit 100 includes a conduit top 10 and a conduit bottom 49. The conduit bottom 49 defines a conduit outlet 4. The conduit 100 is arranged so that particles 1 supplied 2 to the conduit top 10 flow 9 in a downward direction through the outlet 4 to be received 5 by one or more included containers 50 disposed on a movable 61 conveyor belt 60. The conduit hollow 3 includes one or more conduit hollow elements disposed therein. The one or more conduit hollow elements include any of a plurality of agitators 70, 80 and an auger 90. The particle filling line is arranged with means 300 for determining a resistance that is based on the spacing 72, 73, 83 and 94 between the one or more conduit hollow elements 70,80,90 and the conduit inner walls 21,31,41. When the resistance is determined to be less than a threshold resistance value, the particle filling process ceases.

The table below lists the drawing element reference numbers together with their corresponding written description:

REF. NO.: DESCRIPTION

-   1 particles -   2 particles being supplied to the conduit -   3 conduit hollow -   4 conduit outlet -   5 particles being dispensed from the conduit -   7 conduit height -   8 particle source -   9 flow of particles in conduit -   10 conduit top -   20 conduit upper cylindrical portion -   21 conduit upper cylindrical portion inner wall -   22 conduit upper cylindrical portion outer wall -   29 junction of conduit upper cylindrical and conical portions -   30 conduit conical portion -   31 conduit conical portion inner wall -   32 conduit conical portion outer wall -   39 junction of conduit conical and lower cylindrical portions -   40 conduit lower cylindrical (funnel) portion -   41 conduit lower cylindrical (funnel) portion inner wall -   42 conduit lower cylindrical (funnel) portion outer wall -   49 conduit bottom -   50, 51, -   52, 53 containers -   60 conveyor belt -   61 direction of conveyor belt -   70 first agitator -   72 spacing between first agitator and conduit inner wall 21 -   73 spacing between first agitator and conduit inner wall 31 -   80 second agitator -   83 spacing between second agitator and conduit inner wall 31 -   90 auger -   94 spacing between auger and conduit inner wall 41 -   100 conduit -   200 agitator and auger power drive -   210 agitator and auger power drive housing -   220 power drive-housing electrical contact point(s) -   300 resistance determining means -   301 first detector path -   302 second detector path -   310 detector

While various embodiments of a continuity-detecting method of dispensing particles, a particle filling line and apparatus for dispensing particles, in accordance with the present invention, are described above, the scope of the invention is defined by the following claims. 

1. A method of dispensing particles, said method comprising: providing a vertically oriented conduit having a conduit hollow, a conduit top and a conduit bottom, said conduit bottom defining an outlet, said conduit being arranged so that particles supplied to said conduit top flow through said outlet, said conduit hollow including one or more conduit hollow elements disposed therein, said conduit having a detector electrically connected to said conduit and separately electrically connected to said conduit hollow elements, said conduit having a plurality of first electrical contact points electrically connecting said detector and said conduit, and said conduit having a plurality of second electrical contact points electrically connecting said detector and said conduit hollow elements; filling said conduit hollow with particles; flowing said particles through said outlet to be received by one or more included containers; and using said detector to determine a resistance that is based on a spacing between said conduit hollow elements and said conduit hollow.
 2. The method of claim 1, said conduit hollow elements comprising a first agitator, a second agitator and an auger.
 3. The method of claim 1, said conduit hollow elements and said conduit comprising a conductive material, said method further comprising using said detector to determine if said resistance is less than a threshold resistance value.
 4. The method of claim 3, if said resistance is less than said threshold resistance value said method further comprises ceasing said flow of particles.
 5. The method of claim 1, said particles comprising toner.
 6. A method of dispensing particles, said method comprising: providing a vertically oriented conduit being arranged so that particles supplied to a conduit top flow through a conduit hollow to an outlet, said conduit hollow including one or more conduit hollow elements disposed therein, said conduit having a detector electrically connected to said conduit and separately electrically connected to said conduit hollow elements, said conduit having a plurality of first electrical contact points electrically connecting said detector and said conduit, and said conduit having a plurality of second electrical contact points electrically connecting said detector and said conduit hollow elements; flowing said particles through said conduit hollow to said outlet; and using said detector to determine a resistance between said first electrical contact points and said second electrical contact points, said resistance indicating a spacing between said conduit hollow elements and said included conduit inner walls.
 7. The method of claim 6, said conduit hollow elements comprising a first agitator, a second agitator and an auger.
 8. The method of claim 6, said conduit hollow elements and said conduit comprising a conductive material, said method further comprising using said detector to determine if said resistance is less than a threshold resistance value.
 9. The method of claim 8, if said resistance is less than said threshold resistance value, said method further comprises ceasing said flow of particles.
 10. The method of claim 6, said particles comprising toner.
 11. A method of dispensing particles, said method comprising: providing a vertically oriented conduit being arranged so that particles supplied to a conduit top flow through a conduit hollow to an outlet, said conduit hollow including one or more conduit hollow elements disposed therein, said conduit hollow elements and said conduit comprising a conductive material, said conduit having a detector electrically connected to said conduit and separately electrically connected to said conduit hollow elements, said conduit having a plurality of first electrical contact points electrically connecting said detector and said conduit, and said conduit having a plurality of second electrical contact points electrically connecting said detector and said conduit hollow elements; flowing said particles through said conduit hollow to said outlet; and using said detector to determine a resistance between said first electrical contact points and said second electrical contact points, said resistance indicating a spacing between said conduit hollow elements and said included conduit inner walls.
 12. The method of claim 11, said conduit hollow elements comprising a first agitator, a second agitator and an auger.
 13. The method of claim 11, said method further comprising using said detector to determine if said resistance is less than a threshold resistance value.
 14. The method of claim 13, if said resistance is less than said threshold resistance value, said method further comprises ceasing said flow of particles.
 15. The method of claim 11, said particles comprising toner.
 16. A method of dispensing particles, said method comprising: providing a conduit being arranged so that particles supplied flow through a conduit hollow, said conduit hollow including one or more conduit hollow elements disposed therein, said conduit hollow elements and said conduit comprising a conductive material, said conduit having a detector electrically connected to said conduit and separately electrically connected to said conduit hollow elements, said conduit having a plurality of first electrical contact points electrically connecting said detector and said conduit, and said conduit having a plurality of second electrical contact points electrically connecting said detector and said conduit hollow elements; flowing said particles through said conduit hollow; and using said detector to determine a resistance between said first electrical contact points and said second electrical contact points, said resistance indicating a spacing between said conduit hollow elements and said included conduit inner walls.
 17. The method of claim 16, said conduit hollow elements comprising a first agitator, a second agitator and an auger.
 18. The method of claim 16, said method further comprising using said detector to determine if said resistance is less than a threshold resistance value.
 19. The method of claim 18, if said resistance is less than said threshold resistance value, said method further comprises ceasing said flow of particles.
 20. The method of claim 16, said particles comprising toner. 